The present invention is directed to methods and apparatus for dispersing material, particularly granular chemical material. The invention is particularly adapted for dispensing agricultural treatment material, such as pesticides, herbicides, fungicides, and fertilizer from an apparatus driven over the terrain onto which the treatment materials are to be applied.
Agricultural dispensing apparatus, more commonly known as granular spreaders, generally include a wheeled vehicle, either self-powered (e.g., motorized) or manually driven, including a housing having a hopper for receiving a container holding the product to be dispersed, and metering means for controlling the quantity of material flowing from the product container, by gravity feed, and onto dispersing means, such as a rotating plate, positioned beneath the metering means for receiving material deposited thereon. The apparatus is driven along terrain to be treated, and the material to be applied to the terrain is dispersed from the moving apparatus by the rotational forces applied by the rotating plate.
Known agricultural spreaders exhibit disadvantages which include: variations in the rotational speed of the dispersing plate (and thereby variations in the distance which material is propelled from the spreader) in proportion to changes in the linear speed of the spreader; imprecise metering of material deposited on the disperser plate from the product container during repeated dispersing operations; the inability to control the angular orientation at which material is dispersed from the spreader; and the inability to automatically disengage the metering means from the disperser plate to prevent material from being deposited on the disperser plate when the spreader is moved in a reverse direction.
It is the primary object of the present invention to provide an improved spreader, particularly for dispensing granular agricultural materials onto terrain over which the spreader is driven, which overcomes the aforementioned disadvantages, and others, encountered in the operation of known dispersing apparatus. Other objects and advantages of the methods and apparatus in accordance with the present invention will become apparent from the following description of the invention in conjunction with the drawings.
The present invention provides methods and apparatus for dispensing material, and in particular granular agricultural treatment material, from a moving disperser device. The device includes a housing, at least a pair of wheels mounted to the housing for driving the housing over the ground, and a handle by which the device can be driven. The vehicle may be either self-powered or manually driven, and includes a housing having a hopper for removably receiving a product container with the material to be dispersed. Metering means are provided to control the flow of material, by gravity feed, from the hopper and onto a spinning impeller therebelow for propelling the material from the moving apparatus. The metering means includes an apertured disk defining a plurality of concentric rows of vertical channels, each of the vertical channels having opened upper and lower ends. A discharge plate defining at least one opening thereon is mounted below the metering disk, and is operatively associated with the metering disk such that rotational movement of the metering disk relative to the discharge plate selectively covers and uncovers the openings in the lower ends of selected vertical channels in the metering disk. When the lower openings of the channels are uncovered, material in the channels is permitted to flow through the opening in the discharge plate, by gravity feed, to be deposited onto a rotatable impeller therebelow. A charging plate having at least one opening is mounted above the top of the metering disk such that rotational movement of the metering disk relative to the charging plate uncovers the upper ends of selected vertical channels in the metering disk. In this relative position, material from the hopper flows, by gravity feed, through the opened portion of the charging plate to fill each of the selected uncovered vertical channels in the metering disk to its maximum volume. During the filling procedure, the discharge plate beneath the metering disk covers the lower ends of the vertical channels being filled to prevent the material from dropping through the channels. When the channels are filled to full capacity, the metering disk is rotated such that the charging plate covers the top openings in each filled vertical channel to sweep excess material therefrom and to prevent further material from being deposited therein. The discharge plate beneath the metering disk is oriented relative to the charging plate so that when the metering disk rotates relative to the charging plate to cover the upper ends of the filled channels, the metering disk simultaneously rotates relative to the discharge plate to uncover the lower ends of the vertical channels to permit the material in the filled channels to drop downwardly, by gravity feed, onto the rotatable dispersing impeller therebelow. In this manner, a uniform, repeatable quantity of material, corresponding to the volume of the filled vertical channels defined in the metering plate, is sequentially deposited on the dispersing impeller during each filling and metering operation. A drive train couples the metering disk to a wheel of the spreader for imparting rotational movement to the metering disk so that material is metered at a rate corresponding to the linear speed of the spreader and is dispensed in uniform density over the terrain travelled by the spreader.
A selector plate is mounted beneath the discharge plate (which itself is mounted beneath the metering disk) for selectively blocking the lower openings of predetermined vertical channels in the metering disk for controlling the position on which material is deposited from the metering disk onto the rotatable impeller therebelow. The position at which material is deposited on the impeller is a parameter which affects the range or distance that the material deposited thereon is propelled as a result of applied rotational forces. The selector plate maintains the openings in the lower ends of predetermined vertical channels covered without regard to the position of the metering disk relative to the discharge plate, thereby effectively overriding the discharge plate when metering disk is rotated over an opened portion of the discharge plate to uncover the lower openings in the predetermined vertical channels. The selector plate also provides means for selectively blocking different overall sections of the metering disk to adjust the angular orientation at which material is propelled from the moving spreader by the rotatable impeller.
At least one wheel of the spreader is coupled to the impeller to impart rotational movement to the impeller as the spreader is driven over the terrain to be treated, and means are provided for maintaining the actual rotational speed of the rotatable disperser impeller constant and independent of the linear speed of the spreader. In this manner, the distance or range which material deposited on the rotating impeller is propelled, which is proportional to the rotational speed of the impeller, is maintained at a constant value which is selectively adjustable by adjusting the rotational speed of the impeller. In the preferred embodiments of the invention, the means for maintaining the rotational speed of the impeller at a constant value includes a plurality of weights which are movable in guide elements, by inertial forces, relative to the center of the impeller for opposing applied forces to the impeller tending to increase or decrease the rotational speed thereof.
The spreader, in its preferred embodiments, includes a clutch system and associated drive train coupled to one wheel of the spreader for automatically disengaging the meter assembly to prevent material from being deposited on the rotatable impeller when the spreader is moved in a predetermined direction (i.e., in reverse).
The present invention also provides an improved product container for removably mounting onto the hopper of the spreader. The lower portion of the container defines a compartment for accommodating a meter housing including the meter assembly discussed above. In the preferred embodiments of the invention, the container includes a transparent plastic product bag received within a container housing, and a clear section on the container housing to permit visual observation of the contents within the product bag. Because the meter housing and the removable product container are formed as a single unit which is removably mounted to the spreader, the meter assembly can be pre-set to the desired quantity of material to be metered, the desired rate at which material is to be metered, and the desired position at which material is to be deposited on the dispersing impeller, before the product container is mounted to the spreader.
In a further embodiment of the spreader apparatus and product container in accordance the present invention, the spreader includes override clutch means which permit a rotatable impeller to continue to rotate after movement of the apparatus has ceased for dispersing any material remaining on the impeller after the spreader has come to a halt. In this manner, excess residual product deposited on the impeller will not be dispersed from the impeller when the spreader apparatus resumes travel along the terrain to be treated and the impeller resumes rotation.
The spreader apparatus also includes a selector switch readily accessible to an operator for selectively adjusting the rotational speed of the impeller between two or more different pre-selected speeds for adjusting the distance or range which material is propelled from the rotating impeller. An on/off switch for disengaging a drive train coupling the wheels of the spreader to the impeller is operatively associated with the selector switch to assure that the rotational speed of the impeller can not be changed unless the drive train to the impeller is disengaged.
The spreader apparatus also includes a further switch readily accessible to the operator for controlling the area of terrain relative to the spreader apparatus on which material from the apparatus will be dispersed from the rotatable impeller. This switch enables the operator to selectively control the pattern of distribution of material from the impeller plate in a direction predominantly forward of the apparatus, in a direction predominantly to the left side of the apparatus, in a direction predominantly to the right side of the apparatus, in a direction to the rear of the apparatus, or equally distributed to the left and right sides of the apparatus, as may be required by the specific application being made by the spreader apparatus as it moves along the terrain to be treated. The switch also includes an xe2x80x9coffxe2x80x9d position in which no material is distributed. Visual indicia provide the operator with illustrations of the specific mode of operation corresponding to each of the different switch positions.
The spreader apparatus also includes means for enabling the operator to readily align and engage drive shafts in a meter assembly carried by a product container and in the spreader apparatus to permit material to be metered from the product container and dispersed by the spreader as the spreader is moved along terrain to be treated. The spreader apparatus also includes guide elements for assuring that the selector plate which controls the distribution pattern of material dispersed from the spreader apparatus is maintained in proper position relative to the metering disk of the spreader apparatus to assure that the proper quantities of material are metered and deposited on the proper positions on the rotatable impeller.
The spreader apparatus also includes beveled edges on a clutch compartment enclosing a clutch forming part of the drive train between the wheels of the spreader and the rotatable impeller. The beveled edges of the clutch compartment enclose the clutch and tend to muffle and deflect sound waves generated by the clutch in a direction towards the inner surface of the spreader wheels to result in quieter operation of the spreader apparatus as it moves along the terrain to be treated.
The spreader apparatus also includes a drive train coupling the wheels of the spreader to the rotatable impeller having a drive belt with evenly spaced sprocket openings which are engaged by drive pins in a capstan to provide a more positive driving force than provided by O-ring belt designs.
The spreader apparatus also includes hinged flaps which are selectively movable between extended and retracted positions, respectively. The flaps are removably retained in either extended or retracted positions by retaining means which include complementary magnets mounted to the spreader apparatus and the flaps. The flaps are mounted to the left and right sides of the spreader apparatus and are provided to prevent product from drifting into undesired areas when an edge application of material is required during a treatment process.
In a further embodiment of a product container in accordance with the present invention, the product container can be formed from a molded plastic material so as to be re-usable during different treatment operations of the spreader apparatus. The container can be designed to include a lower rolling lip structure to be removably received in a flange of a meter assembly for readily connecting and disconnecting the meter assembly from the container. The container and the meter assembly include cooperating structure by which the meter assembly is maintained in a fixed position relative to the container when the meter assembly and container are coupled to each other.
The container also includes a domed or spherical partition mounted proximate to the bottom of the container f or preventing the full weight of product in the container from being applied directly to the meter assembly carried by the bottom of the product container. This partition supports the weight of all product in the container positioned thereabove. The partition also includes at least one slot or aperture for controlling the downward flow of material from above the partition and onto the meter assembly positioned below the partition. The partition rotates together with the meter disk and tends to break up lumps of material into smaller granules as the material flows downwardly by gravity feed through the opening in the rotating partition.